It is known to provide container seals for preserving the contents of the container prior to opening. In many cases the seal is pierced to gain access to the product. When the seal is pierced, the material of the seal may come into direct contact with the product. Depending on the type of seal there may be certain layers which must be present in order to provide it with certain properties, such as the ability to be sealed to the rim of the container and the ability to prevent ingress and/or egress of material to and from the product. These requirements may conflict with the desire to avoid contact of certain materials in the seal with the product.